Pipes as Structural Columns

[Zambo]

I'm having a bit of a problem buying pipe to be used as structural columns (in fact they will be filled with concrete and later encased in concrete).

The thing is there are so many specs for pipe, generally for use as pressure pipe. I want to use European Standard, but how to find which spec is suitable (for example I don't need expensive seamless pipe).

This might seem vague but I think there is specific knowledge which for some reason has passed me by - is it tube or pipe?

 

[Lion06]

I don't know about the European standard, but in the U.S. "pipe" is only good for 35 ksi yield. Round HSS is good for either 42ksi or 46ksi.

 

[Zambo]

StructuralEIT,

thanks for your response. This is where I'm getting stuck... now 3 terms pipe, HSS and tube. I am looking for a website that describes these terms (unless simeone can do here). The steel grades are easy, the problem is what happens when you get into pipe standards.

 

[Lion06]

check out

http://www.aisc.org

I am sure there is information there. I don't think the term "tube" is used anymore. HSS is for "Hollow Structural Section". This replaced "tubes" recently. I am not sure of the exact difference between HSS and tubes, but I think it has to do with slight dimensional changes.

 

[Zambo]

I will try the website for aisc. I would call the section I need CHS - Circular Hollow Section but how to define the product. I think seamless pipe is the most expensive, followed by cold formed with a longitudinal seam down the circumference and then I belive the cheapest is spiral welded.

For each of the 3 production methods I list above I think any grade of steel could be used. I want to use British Standard 50B steel, but then I get confused about the pipe standard.

 

[Lion06]

I don't think you need to worry about the pipe standard. The different section should be available using different types of materials. I don't think you will specify how they fabricate the section. That is all done through standards (hence ASTM A500 Gr. B for a HSS in America). As long as that standard is met, you needn't worry about it.

 

[csd72]

I think that your problem her is referring to it as pipe. The US is the only place I know of that uses pipe sections for structural purposes.

Elsewhere you would normally refer to it as a circular hollow section (or CHS).

csd

 

[Zambo]

csd72,StructuralEIT,

so if I sepcify the grade of steel, wall thickness and diameter then I will get the required structural properties regardlees of the method of fabrication?

What I want to use is spiral welded, but the specification given by the designer is hot finished, cold formed pipe which does not include spiral welded this is a single process without hot finishing.

 

[Lion06]

do you really care about the fabrication process if the end result is what you need?
The fabricators know alot more about that than we do.

 

[valleyboy]

Hello Zambo

It sounds like you need to specify a hot rolled structural hollow section to EN10025:2004.

See the attached link for a description of steel specifications to this standard. You mention the use of Grade 50B steel, which is the older BS 4360 designation - there is an equivalence table in this publication which may assist.

Hope this helps.

http://www.corusgroup.com/file_sour...oducts/Sections/Steel standard EN10025-04.pdf

VB

 

[shin25]

Zambo,

Why don't you give a call to the designer and ask him to clarify his intent? You also can describe him your process and request him to comment on this.